1. Field of the Invention
The present invention relates to a vehicular air conditioning apparatus mounted in a vehicle for blowing air into a vehicle compartment that has been adjusted in temperature by a cooling means and a heating means, for thereby adjusting temperature of the vehicle compartment.
2. Description of the Related Art
In a vehicular air conditioning apparatus that is mounted in a vehicle, internal and external air is introduced into a casing by a blower, and after cooled air, which has been cooled by an evaporator that forms a cooling means, and heated air, which has been heated by a heater core that forms a heating means, are mixed together in the casing at a predetermined mixing ratio, the mixed air is blown out from a defroster blow-out port, a face blow-out port, or a foot blow-out port, whereby adjustment of temperature and humidity in the vehicle compartment is carried out.
Generally, with the aforementioned vehicular air conditioning apparatus, for example as disclosed in Japanese Laid-Open Patent Publication No. 2003-220820, the defroster blow-out port is arranged on the front side of the vehicle in the vicinity of the front window, for carrying out removal of fog (condensation) from the window by blowing air from the defroster blow-out port, whereas the vent blow-out port for blowing air toward passengers in the vehicle compartment is arranged more rearwardly in the vehicle with respect to the defroster blow-out port for cooling the vicinity of faces of passengers by blowing air from the vent blow-out port.
However, with the above vehicular air conditioning apparatus, because warm air that is heated by the heater is mixed with cool air that is blown so as to circumvent the heater, the passage on the downstream side of the heater generally is formed in a curving manner, so that a large ventilation resistance occurs when air flows through this passage. Further, recently, there has been a demand to increase the blowing rate of air that is blown into the vehicle compartment by reducing such ventilation resistance inside the passage.
Further, in a conventional large-sized vehicle, one vehicular air conditioning apparatus is disposed in each of the front and rear sides of the vehicle, separately, and the front and rear sides of the vehicle compartment are air-conditioned independently. However, in response to a demand for a further widened vehicle compartment, a single vehicular air conditioning apparatus equipped with two blowers has been provided in recent years. The two blowers flow air toward two independent passages connected to the front and rear sides of the vehicle compartment, respectively. Because two independent passages are provided for a single vehicular air conditioning apparatus, the cross-sectional area of each independent passage becomes small. In addition, air flow resistance for the air flowing through the independent passages is high due to bent and complex shapes of the passages.